The Cavs play good team defense. They have excellent interior size plus a very active, athletic jumping jack in LeBron who covers a lot of ground very quickly. They rebound better than most teams and get lots of 2nd chance points to help out their inept team offense.
If the Cavs can shoot a decent percentage, it will be a tough series. If not, the Spurs should be able to get out and run and win in big-time fashion. The Cavs just have a way of throwing a wrench into normally easy scoring positions. Since the Cavs play a similar defensive scheme to the Spurs, they see the Spurs defense in practice. My heart says one thing but my eyes, my reason and basketball sense say another. The series could turn ugly.